Compartment (chemistry)

In chemistry, a compartment is a part of a protein that serves a specific function.

There may be multiple compartments on one and the same protein. One example is the case of Pyruvate dehydrogenase complex. This is the enzyme which catalyses Pyruvate decarboxylation, the reaction of Pyruvate with Coenzyme A and the major entry point into the TCA cycle:

Pyruvate + Coenzyme A + NAD⁺ ⇒ acetyl-CoA + NADH + H⁺ + CO₂

Pyruvate dehydrogenase has three chemical compartments; E1 (pyruvate decarboxylase), E2 (dihydrolipoyl transacetylase) and E3 (dihydrolipoyl dehydrogenase). Each one of the compartments has its own specific function.